Biodiversity is our life, the reason why the year 2010 was celebrated as the international year of biodiversity. Biodiversity offers enormous opportunities for environmental sustainability and sustainable development and is the basis for essential environmental services upon which life on earth depends. Thus, its conservation and sustainable use are of critical importance as it is one critical area to achieve sustainable development. In spite of their important ecological functions as habitat for many biodiversities, tropical montane rain forests in Cameroon's North Western Highlands are threatened by over exploitation and rapid deforestation and degradation mainly as a result of human-induced developmental factors resulting to habitat destruction and loss. This study was aimed at examining the roles or potentialities of tropical montane rain forest biodiversity to environmental sustainability in Cameroon's North Western Highlands. This was accomplished through a review of published literature and field work, as well as descriptive analyses of collected data. Our results showed that the Cameroon North Western Highlands tropical montane rain forest is a habitat containing many species which makes it resilient to environmental shocks through catchment/watershed preservation, maintains food chains via energy transfer, stabilize soils from erosion, storms, flood and drought, moderate global temperatures thereby preventing global warming and provides a storehouse of genetic materials that is of enormous importance to human activity such as agriculture and medicine. The study highlights that the forest stand as a nursery and good breeding ground for multiple biological taxa that should be conserved and ensure its rational use for sustainable development through arresting the loss of biodiversity, provide funding through networking with new partners such as NGOs, charities and international companies for conservation and forgone alternatives in the various developing countries and conduction research into setting priorities for the conservation and sustainable utilisation of biodiversity in the region.